Process of purification of hydrocarbons



L. EDELEANU ET AL PROCESS 0F PURIFICATION OF HYDROCARBONS 2 Sheets-Sheet 1 Filedmggne 21. 1922 Inventors L.EdeZ0ai/u,

1,526,665 L. EDELEANU ET AL PRocEss 0F.PURIFICATION oF HYDROCARBONS Filednqune 2l. 1922 v 2 Sheets-Sheet 2 Feb. 17. 1925.

NOW,

Inventors Patented Feb. 17, 1925.

UNITED STATES PATENT OFFICE.

LAZAR EDELEANU, OF CHARLOTTENBURG, AND WILHELM HESE, OF LICHTERFELDE,

' f GERMANY.

PROCESS OF PURIFICATION OF HYDROCAEBONS.

Application filed .Tune 21, 19%2. erial No. 569,921.

To all who-m, t may concern.'

Be it known that we, LAZAR EDELEANU, a citizen of Rumania, and resident of Charlottenburg, Germany, and `WIL111-1LM Hass, a

citizen ot' the. Republic ot' Germany, and

resident of Lichterfelde, '(leriuany, have invented an Improvement in Processes of Purification of Hydrocarbons, of which the following description is a specification, like l@ characters on the drawings representing like parts.

life do hereby declare the nature ot' this invention and in what manner the same is to be performed, to he particularly described i 'i and by the following statement:

'lhis invention relates to a process for the separation of hydrocarbons readily soluble in liquid sulphur-ous acid from hydrocarbons which are soluble with difliculty or insoluble 20 in liquid sulphurous acid (sulphur dioxide),

which as is known` effects an efficient purification from undesired ingredients.

ln the purification of mineral oils with a high boiling point by means ot' the usual sulphur-ous acid process, such, for example, as that described in United States Patent No. 911.553, the resinifviug materials contained in heavy mineral oils can only be completely removed by re eatcd extractions 3o with the help of fresh iquid sulphurous acid. Apart from the fact that the repeated extractions with fresh liquid sulphurous acid is connected with loss ot' valuable ingredients ot' the original material, arising from the fact that to a certain degree saturated hydrocarbon products are extracted, such repeated extractions render the product more expensive, as thc recovery of the large quantities of sulphurous acid required for 40 therepeated operations is of itself very costly. i

The: main object of tht` invention is to roy vide a process which will allow the puri 'ca- ,lion to vbe effected more completely and more economically.

. y `ithl this object in view the invention co ists rin subjecting the primary materials i cated extractions in one and the same Y with liquid sulphurous acid saturated erent degrees with the resinifying materials which it is desired to remove` the first extraction being effected with a liquid sulphurous acid of the highest degree of saturation as compared with the saturation of the liquid sulphurous acid used for the sub- M sequent extractions, which extractions are followed by a final extraction with pure liquid sulphurous acid. The final extraction may advantageously be effected in a separate vessel. v im lt will thus be seen that in the recess according to the present invention tor the first extraction a liquid sulphurous acid is used which already contains substances easily soluble in liquid sulphurous acid (unmi saturated hydrocarbons) the removal of which is the object of the process, but which has also absorbed substances not so readily soluble in liquid sulphurous acid (saturated hydrocarbons) and the removal of which l@ would be disadvantagreous and uneconomical. In applying the inventionto'the purification of mineral oils of high boiling point. the first extraction may be effected by such liquid sulphurous acid which has already m been used three times in preceding extractions; thereupon a second and third extraction are effected with liquid sulphur-ous acid that has been used twice and once respectively for the same purpose; the final treatau ment is then effected with unused liquid sulphurous acid, which after this final extraction is reserved for use in a following operation, as above described. In this manner an effiiient separation into two parts is effected, @El the one part being soluble in liquid sulphurous acid (extract), and the other part being insoluble therein (refined product). However, the liquid sulphurous acid contains not only the materials that it is desired to remove (the unsaturated compounds) but also a certain proportion of the material it is desired to retain. and we have 'found that such li uid sulphurous acid has the property that, when it is againbrought into contact with the materials to be treated it removes the unsaturated compounds without being enriched in the compound it is desired to retain. Apart from the fact that an exhaustive purification of the mineral oils is thcreby achieved, the quantity of liquid sulphurous acid to be evaporated is small as compared with the quantity of oil to be treated. Any known form of apparatus can be used for carrying out the process, which comprises intermediate vessels for the various 'quantities of liquid sulphurous acid and coriesponding conduits connected with the mixer.

The accompanying drawings illustrate two forms of apparatus which can be used for this purpose; and

Fig. 1 shows .diagrammatically a form of e ected in a single vessel, Whilst Fig. 2 illustrates a modification in which the final extraction is effected in a separate vessel.

In the drawings, a is the extracting vessel, c the extract evaporator, f the evaporator of the refined product; d ande are the vessels for storing the various extracts the number of which vessels may be increased if required; g isfa vessel in which' the sulphurous acid gases coming from Gand f are condensed; L 1s a, reservoir for the liquid sulphurous lacid condensed 1n g; and z 1s the -pump by means of which the second-and .addition to constituents soluble in liquid sulphurous acid, also constituents insoluble therein. Among such substances are, for instance, lignite tar oil, and particularly the product'which remains during the gasification of the lignite at low temperatures. But also other products complying with the requirements above mentioned may be considered as suitable materialsto be subjected to the purification process according to the resent invention. 1s known to be rich in paraffin, which is insoluble in liquid sulphurous acid, while all the other constituents are soluble therein. In this case, owing to the low melting point of paraiiin, the method can easily be worked as hereinafter explained.

The tar to be treated, or its distillate, is

`mixed in the extracting vessel a with a large volume of liquid sulphurous acid, and cooled down to 10 C. After standing for some time the liquid is separated at the bottom and the solid fine crystals of 'paraffin float on the surface. The clear extract is then allowed to ass through the filterress b (the latter gat ering solitary crystals to the vaorizerc; the progress of the process can be ollowed through a glass window in the lowaparatus in which all the extractions are` Thus crude lignite tary er part of the vessel a. Subsequently another quantity of liquid sulphurous acid is admitted to the vessel a, the contents of which are stirred for a short time; then the lower layer, the so-called extract II, is passed intov the reservoir d. It is not necessary to 'Wait for the complete separation of the layers, and likewise the exact temperaturetobe maintained is also of little importance since this extract II will again be used in the following operation as extract I, and will thereby be cooled down again to -10; it is therefore immaterial whetherthe extract takes or not with it,.slo.ne of the paraffin either in consequence of incomplete separation or on account of the temperature beingr too high. l

The liquid sulphurous acid is then passed into the container a for a, third time, but this time the contents are warmed up to 40o C. during the process of mixin The parafin melts to a clear layer and can thus be separated without diiiiculty from the extract III. The latter is passed into the reservoir e, while the paraffin flows into the vaporizer f.' Extract III serves in the next operation as extract II.

The liquid sulphurous acid'is expelled by heating from the extract vaporizer c and the va-porizer f, reduced pressure beingA applied towards the end of the evaporation; thcl products thus obtained viz the parati'in-frec extract and the paratiin itself, are then rcmoved inthe usual way.

Insteadv of heating the contents of thc container a` to 40 C. in the final extraction for the purpose of melting the paraffin' and separating it from the extract III, such heating at 40 C. may be effected in the first or at least the second extraction. rllhis,

lon

however, is impractica-ble in treating oils containing paraffin because the liquid sulphurous acid, mixed with the soluble oil constituents, exhibits a-strong capacity 'for dissolving parain lat increased temperature. Consequently a comparatively large' quantity of parain would be dissolved with that particular extract. In contradistinction thereto, extract III which contains only a small portion of oil. i. e. .consisting almost entirely of liquid sulphurous acid, dissolves only a small quantity of paraffin even at 40 C. l t

lrVhenv the operations are effected in quick succession there may be loss of time since the extracting container` is correspondingly heated, throu hthe heating of extract III to 40 C. and su sequently has first to be cooled down to -10 C. for extract I ofthe following operation.

In order to avoid this, a second extractingv vessel a1 may be added, into which the contents of the vessel a are introduced-,oli drawn in by means of the gas pump, while-in the second container a1 (Fig. 2) -which is similar to the container a-the treatment with liquid sulphurous acid is applied at 40 C., so that it is not necessary to warm a. The second container a1 must be suitably connected to the rest of the apparatus by means of the necessary'conduits. Y

The process may also be applied to the extraction of pure anthracene from crude anthracene as used in commerce, whereby Without much loss of anthracene a S12-94% pure -anthracene can be extracted from the commercial anthracene containing only 40% of pure anthracene.

In this case, the production of the final extraction differs from the extraction of paraffin, since the high melting point of 4anthracene does not lallow it to be melted in the apparatus. The removal of the anthracene from the mixer to the vessel intended for the evaporation and complete expelling vof the liquid sulphurous acid, is best effected lis effected in thesame manner as prescribed for anthracene.

The examples hereinbefore described, show the man v possible applications of the process according to the present invention. All solid bodies Vwhich are lighter than liquid sulphurous acid can be treated similarly to crude anthracene and Montan wax; oils containing both solid constituents insoluble in liquid sulphurous acid and liquid constituents which are soluble, are treated in the same manner as described in connection with crude tar.

` Advantages of the improved process are, first, that the temperature and pressure conditions in the extracting vessel or vessels may be controlled independently for the crude material and for each` successive portion of extract treated; second, the loss of saturated hydrocarbon compounds carried off in the extract in the treatment afterv the first addition otsulfurous acid is negligible because the acid.- is already carrying its capacity and givesfbacl: to the product in' the extracting vessel. as much fas it dissolves of such compounds; third, the volume of spent' acid'that must be vaporized, exhausted and condensed is diminished by two-thirds or more, depending upon the number of. pol-,

tions of extract stored for re-use, and the volume of fresh sulfurous acid needed for complete separation of the aromatic and resinous unsaturated compounds from the clear saturated compounds is correspondingly less than heretofore required, thereby reducing the cost of the treatment; and fourth, the output and purity of the refined product is greater for the same capacity plant.

Claims.

1. The p-rocess of separating hydrocarbons into a part soluble in liquid sulphurous acid and a part insoluble or hardly soluble in the same by dividing the material into'portions for successive treatment which comprises the step of bringing liquid sulphurous acid at a temperature Well below7 its vaporization point, which has already been in contact. with a portion of the primary material and contains not only constituents of the first-named part but also constituents of the second-named parts, agaih into contact with another portion ofr the p-rimary material fresher than that with which said acid has already been in co tact whereby unsaturated compounds of t e first-named part are removed from said fresher portion without removing therefrom compounds of the second-,named part. y

2. The process of separating undesired ingredients froml hydrocarbons by means of liquid sulphurous acid which consists in the systematic subjection of the primary material to extraction in batches at a temperature Well below the vaporization point of sulphuro'us acid in a number of successive stages with mother liquors arising from previous extractions of different degrees of saturation commencing with a liquor having the highest degree of saturation followe by a final extraction with pure liquid sulphurous acid, whereby the loss of hydrocarbons in solution with said undesired ingredients is lessened.

3. The process of purifying the liquid parts and of separating solid compounds in a purified state from complex hydrocarbon products by means of liquid sulphurous acid characterized by the primary material being systematically extracted in batches at a low. temperature in several successive stages with mother liquors arising from previous extractions of different degrees of saturation beginning with that most highly saturated with extracted substances, and finally with pure liquid sulphurous acid, whereby the loss of desirable component-s is lessened, substantially las described` 4. The process of separating paraiiin from lignite tar or its distillate which consists in mixing a relatively large volume of liquid sulphurous acid with the primary material in au extracting vessel cooling down the mixture and allowing it to stand removing the clear extract through a filter to a vaporizer, subsequently' adding a second quantity of liquid sulp-hurous acid tosthe vessel stirring the mixture and subsequently removing the lower layer and storing the same, addin a third quantity of liquid sul phurousaci to the vessel and warming the p mixture while stirring removing the extract and separately storing it passing the clear layer of paraffin to a second vaporizer expelling the liquid sulphurous acid from both vapor1zers by heating and in subsequent operationsutillzing in each succeeding operation the 'extract first 4stored in the previous operation for the rst extraction and the secondlyy storediv extract for the second extraction.

5. The process of separatingparaiiin from lignite tar or its distillate which consists in lnixing a relatively large volume of liquid sulphurous-acid with the primary material in an extracting vessel cooling down the mixture to 10 C. approximately, and allowing it to-stand, removing the clearextract through a filter to-a vaporizer, subsequently adding a second quantity of liquidsulphurous acid to the vessel stirring 4the mixture and subsequently removing the lower layer and storing the same, adding a third quantity of liquid sulphurous acid to the vessel and warming the mixture to approximately 40 C. While stirring removing the extract and separately storing it passing the clear layer of paraiiin to a second va orizer expelling the liquid sulphurous acid from both vaporizers by heating and inA subsequent operations utilizing in each succeeding operation the extract first stored in the previous operation for the first extraction and the secondly stored extract for the second extraction.

6. T'he process of separating paraiiin from lignite tar or its distillate which consists in mixing a relatively large volume of liquid sulphurousacid with the primary material inf@ an extractingvessel lcooling down'the mixture and allowing it to stand, removing the clear extract through a filter to a vaporizer, subsequently adding a second quantty of liquid sulphurous acidto the vessel stirring the mixture and subsequently re.- moving the lower layer and storing the same, removing the remainder from said extracting vessel to a second extracting vessel, adding a third quantity of liquid lsulphurous acid to said second extractingvessel and warming the mixture while stirring removing the extract and separately storing it passing the clear layer of paraffin to a second vaporizer expelling the liquid sulphurous acid from both va-porizers by heating-and in subsequent operations utilizing lin each succeeding operation the extract first stored inthe previousoperation for the first extraction and the secondly stored exi' s tract for the second extraction.

7. The process of separating hydrocarbons into a part soluble in liquid sulphurous acid` and appart insoluble or. hardly soluble in the same which consists in mixing a relatively large volume of liquid sulphurous acid with the primary material in an extracting vessel, cooling down the mixture and allowing it to stand, removing the extracting vessel, coolingr down the mixture and allowing it to stand,'removing the extract to a Vaporizer, subsequently adding a second quantity of liquid sulphurous acid to the Vessel, stirring the mixture and subsequently removing the extract and separately storincf the same, washing and removing the insoluble part from the vessel to a second vaporizer, expelling the liquidsulphurous acid from both vaporizers by heating and in subsequent operations utilizing in each succeeding operation the extract first stored in the previous operation for the first extraction and pure liquid sulphurous acid for the final extraction.

8. The process of separating hydrocarbons into a part soluble in liquid sulphurous acid and a part insoluble or hardly soluble in the same which consists in mixing a relatively large volume of liquid sulphurous acid with the primary material in an extracting vessel. cooling down the mixture and allowing it to stand, removing the extract to a vaporizer, subsequently adding a second quantity of liquid sulphurous acid to the vessel, stirring the mixture and subsequently removing the lower layer and storing the same separately, adding a third quantity of liquid sulphurous acid to the vessel and stirrlng the mixture, removing the extract and separately storing the same, washing and removing ythe insoluble part from the vessel, to a second vaporizer, expelling the liquid sulphurous acid from both vaporizers b vheating and in subsequent op` erations utilizing in each succeeding op eration the extract first stored in the previous operation for the first extraction and the secondly stored extract for the second extraction.

9. The process of separating hydrocarbons into a part soluble in liquid sulphurous acidand a part insoluble or hardly soluble .in the-same which consists in mixing a relai andseparately storing it, passing the layer down the mixturev of insoluble residue to a second vaporzer, expelling the liquid sulphurous acid from both vaporizers by heating and in subsequent operations utilizing in each succeeding operation the extract first stored in the prevlous operation for the first extraction und the secondly stored extract for the second extraction.

In testimony whereof they have signed their naines to this specification.

L. EDELEANUg DR. WILHELM HESS. Witnesses:

LAURENCE A. HANSEN, R. T. AUSPEED. 

